1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device enabling favorable burying growth and selection growth without growing a group III-V compound semiconductor film on an insulating film used as a mask.
2. Background Art
In semiconductor devices such as semiconductor laser elements and modulators, a mesa structure is often formed to limit the range of a current supply region for efficiently confining light or electric current in an active layer. In this case, from a viewpoint of the improvement of heat dissipation, the reduction of electrical capacity, or the protection of the mesa shape, a buried mesa structure wherein a mesa structure is selectively buried in a semiconductor film is often adopted.
In a process for manufacturing such a buried semiconductor device, a semiconductor film is etched using a patterned insulating film as a mask to form a mesa structure, and the mesa structure is buried in the semiconductor film using the insulating film as a mask for burying.
However, if a mesa structure is buried in a group III-V compound semiconductor film, crystals are grown on the insulating film depending on growing conditions, and a subsequent step for removing the insulating film is interfered. Particularly when an Al-containing semiconductor material such as AlInAs and AlInP, is used for the group III-V compound semiconductor film, the growth of crystals on the insulating film is significant. Also when a group III-V compound semiconductor film is selectively formed on a semiconductor substrate using a patterned insulating film as a mask, the similar problem is caused.
Heretofore, by the adjustment of growing temperature (for example, refer to “Selective Growth of InAlAs by Low Pressure Metalorganic Vapor Phase Epitaxy”, M. Tsuji, K. Makita, T. Takeuchi, K. Taguchi, Journal of Crystal Growth, 162 (1996), p. 25), or the introduction of a gas having an etching effect together with a semiconductor material gas into a reactor during crystal growing (for example, refer to “Novel Selective Area Growth of AlGaAs and AlAs with HCl Gas by MOVPE”, K. Shimoyama, Y. Inoue, K. Fujii, H. Gotoh, Journal of Crystal Growth, 124 (1992), p. 235), the growth of the group III-V compound semiconductor film on the insulating film has been prevented.